Implement for extracting dental crowns, bridges and the like

ABSTRACT

An implement for extraction of crowns or bridges from the mouths of dental patients has one or more pairs of jaws and/or one or more hooks or a flexible wire engageable with a crown or bridge at a distance from the edge of the crown or bridge and at a distance from the gums of the patient, and a force applying unit which can pull the jaws and/or the hook or hooks or the wire in a direction to lift the crown or the bridge off the respective tooth or teeth. The jaws can engage spaced-apart portions of external surfaces of crowns, and the hook or hooks or the wire can engage the connector or connectors between neighboring crowns of a bridge.

BACKGROUND OF THE INVENTION

The invention relates to implements or instruments for extractingbridges, crowns and/or other dental restorations or prostheses from themouths of dental patients.

Extraction of bridges, crowns and similar prostheses is a task whichmust be carried out by a physician or by a skilled technician. Theimplements which are presently available for the performance of suchtasks are not entirely satisfactory. As a rule, a presently knownimplement includes or constitutes a hook which is caused to engage theedge bounding an opening of the bridge or crown adjacent the gums of thewearer, and the implement is thereupon pulled, either steadily or instages or steps, in a direction to lift the crown or the bridge off thematerial which bonds the prosthesis to the tooth or teeth of thepatient. The crowns or bridges are normally made of a metallic materialor a metal-ceramic compound. Removal of such prostheses is necessary inthe event of damage, excessive wear, inflammation or infection of thegums or teeth and/or damage to the material which bonds the prosthesisto the tooth or teeth.

A drawback of an implement which employs or constitutes a hook is thatit is highly likely to damage the gums of and to cause great discomfortto the wearer of a prosthesis. Moreover, and since the wall of a crownor bridge is normally extremely thin (as a rule, the thickness is in therange of 0.2 mm), the hook is likely to damage the edge which is engagedthereby and which is acted upon by the hook during separation of theprosthesis from the bonding material within and/or around it. Stillfurther, the hook is highly likely to tilt the prosthesis and to thuscause even more damage as well as to encounter greater resistance as theextracting operation proceeds. Such tilting causes extensive damage tothe tooth or teeth and to the bonding material between the tooth orteeth and the prosthesis. The situation is not changed if the extractiontakes place in stages, e.g., by resorting to a hammer which repeatedlystrikes an anvil at that end of the handle for the hook which is remotefrom the prosthesis. Injury to the gums as a result of engagement of ahook with the edge of a bridge or crown can cause inflammation orinfection which must heal before the removed prosthesis or a freshprosthesis can be inserted into the mouth.

Any, even slight, damage to a crown or bridge during extraction must beattended to subsequent to extraction at a considerable cost. The damagearises not only at the edge which is engaged by the hook but also at theceramic coating (if any), and additional damage is observable on thebonding material.

German Utility Model No. G 88 108 805.8 of (published Dec. 1988)discloses a looped wire the ends of which are held in a housing andwhich is to be placed around a connection between two joined crowns of abridge. The housing carries a guide for a reciprocable hammer which iscaused to repeatedly strike an anvil in order to loosen the bridgepreparatory to complete extraction from the mouth of a wearer. Theimplement of the German Utility Model exhibits the drawback that it isdifficult to secure the looped wire to the housing subsequent to placingof the wire around the connection between two crowns of a bridge.

OBJECTS OF THE INVENTION

An object of the invention is to provide a simple, compact andinexpensive implement for extraction of prostheses (such as crowns orbridges) from the mouth of a patient.

Another object of the invention is to provide an implement which is lesslikely to damage a prosthesis than heretofore known implements.

A further object of the invention is to provide an implement which isdesigned to avoid injury to the gums and to avoid damage to the bondingmaterial between the prosthesis and to the tooth or teeth of a patient.

An additional object of the invention is to provide an implement whichis constructed and assembled and can be used in such a way that it isless likely to change the orientation of a prosthesis during extractionfrom the mouth of a patient.

Still another object of the invention is to provide an implement whichis designed to simultaneously engage a prosthesis at a plurality ofdifferent locations.

A further object of the invention is to provide an implement which neednot touch the gums of the wearer of a prosthesis or an edge of theprosthesis preparatory to and/or during extraction of the prosthesis.

Another object of the invention is to provide an implement which canengage and exert a pull upon a defective, worn and/or otherwise affectedprosthesis in a number of different ways.

An additional object of the invention is to provide a novel and improvedmethod of extracting bridges, crowns or other types of dental prosthesesor dental restorations from the mouths of the wearers without the riskof injury, infection and/or damage to the prosthesis and/or bondingmaterial.

A further object of the invention is to provide a method whichfacilitates rapid and painless extraction of prostheses.

Still another object of the invention is to provide an implement orinstrument which is simple to use and easy to take apart for thepurposes of cleaning, inspection or modification.

A further object of the invention is to provide an implement which canbe manipulated to extract a crown or a bridge in such a way that theextracted part can be reinserted without the need for any repair workattributable to extraction from the mouth of the patient.

SUMMARY OF THE INVENTION

The invention resides in the provision of an implement or instrument forextracting dental prostheses (e.g., damaged crowns or bridges) of thetype affixed to at least one tooth and having at least one portion whichis spaced apart from the gums of the wearer of the prosthesis. The atleast one portion can include two spaced-apart sections of the externalsurface at opposite sides of a crown or the bonded (e.g., soldered)connector or connection between two neighboring crowns of a bridge. Theimproved implement comprises a first unit including at least oneextracting member or element which is engageable with the at least oneportion of a prosthesis to be extracted, and a second unit includingmeans for applying to the at least one extracting element a force in adirection away from the gums of the wearer to thereby separate theprosthesis from the at least one tooth.

The at least one extracting element can include a hook which can becaused to engage the aforementioned bonded connection between twocrowns, and the force applying means of such implement can comprise ahandle which is rigid with or is articulately connected to the hook.

Alternatively, the first unit can include two extracting elements andeach such extracting element can include a jaw. The force applying meanscan include means for moving the jaws between first (spaced apart)positions in which the jaws provide room for the at least one portion ofa prosthesis between them, and second (closed or operative) positions inwhich the jaws clamp the at least one portion of the prosthesis betweenthem; the jaws can engage two portions of the aforementioned externalsurface at opposite sides of a crown). At least one of the jaws cancomprise an elastic prosthesis-engaging portion or pad. Alternatively,at least one of the jaws can be provided with a roughenedprosthesis-engaging surface; the surface can be roughened by beingserrated and/or by being connected with (e.g., by having embeddedtherein) minute fragments of diamonds or another very hard substance.

The jaws can be provided with elongated arms, and the moving means cancomprise a sleeve which surrounds and is slidable along the arms. Thesleeve can be replaced with an internally threaded nut which surroundsthe arms of the jaws.

It is also possible to employ an implement in the form of shears havingtwo elongated halves each including a handle at one end and carrying oneof the jaws at the other end. The shears further comprise means forpivotally connecting the two halves to each other intermediate the endsof the halves.

If the first unit includes a plurality of extracting elements (e.g., oneor more pairs of jaws and/or one or more hooks), the force applyingmeans can include means for movably coupling the extracting elements toeach other. Such coupling means can include at least one annular memberand/or at least one weighbeam.

The at least one extracting element can include an elongated flexibleelement having a first end and a second end, and the force applyingmeans of such implement preferably comprises a housing having means foranchoring the ends of the flexible element therein subsequent to loopingof the flexible element around the at least one portion of a prosthesisto be extracted, e.g., around the aforementioned bonded connectionbetween two neighboring crowns. The ends of the flexible element caninclude or constitute heads, and the anchoring means can include twospaced-apart sockets which are provided in the housing, one for each endof the flexible element and each having an enlarged portion for therespective head. The anchoring means can further comprise means forreleasably confining at least one of the heads in the enlarged portionof the respective socket. Such confining means can comprise a screw oranother threaded member which mates with the housing and preventsextraction of the one head from the enlarged portion of the respectivesocket. Alternatively, the confining means can comprise a closure (e.g.,a lever, a washer or the like) which overlies the enlarged portion of atleast one of the sockets.

The flexible element can include a length of metallic wire having afirst diameter which is slightly smaller than the diameters of holes orbores which are provided in the housing and each of which forms part ofone of the sockets. The diameter of at least one of the heads can exceedthe diameter of a hole or bore.

The second unit can further comprise means (such as a standard dentist'stool with a handle and a hook at one end or at each end of the handle)for pulling the housing. To this end, the housing preferably comprisesat least one portion (e.g., a recess, a hole and/or a yoke) which isengageable by the pulling means.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved implement itself, however, both as to its construction and themode of utilizing the same, together with additional features andadvantages thereof, will be best understood upon perusal of thefollowing detailed description of certain presently preferred specificembodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a portion of a first extractingimplement wherein the first unit comprises two extracting elements inthe form of jaws which are in the process of engaging two spaced apartportions of the external surface of a crown;

FIG. 2 is a perspective view of a second implement wherein the firstunit comprises three pairs of jaws one of which is maintained inengagement with a crown;

FIG. 3 is a perspective view of a third implement wherein the first unitcomprises three pairs of jaws and two hooks, and the second unitincludes a weighbeam pivotably mounting the hooks and the arms of thejaws;

FIG. 4 is a perspective view of a fourth implement in the form ofscissors with a single pair of jaws;

FIG. 5 is a perspective view of a portion of a further implement whichis designed for extraction of bridges;

FIG. 6 is a fragmentary elevational view of a further implement which isalso designed for extraction of bridges and wherein the first unitcomprises three discrete hook-shaped extracting implements;

FIG. 7 is a plan view of a bridge which is composed of a substantialnumber of interconnected crowns and can be extracted with an implementof the type shown in FIG. 6;

FIG. 8 is a side elevational view of an implement which can be used forthe extraction of bridges and wherein the first unit comprises anelongated flexible element;

FIG. 9 is an end elevational view of the implement of FIG. 8, andfurther showing two hook-shaped devices which can be used to exert apull in a direction to extract a bridge from the mouth of the wearer;and

FIG. 10 is a sectional view substantially as seen in the direction ofarrows from the line X--X of FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a portion of an implement 1 which is designed to extractcrowns 3 from the mouths of patients. The illustrated crown 3 is assumedto surround a portion of a tooth and is further assumed to be secured tosuch tooth portion by any suitable bonding material, not shown. Thecrown 3 has an opening surrounded by an edge 3a which is closely orimmediately adjacent to the gums on the upper or lower jaw of thepatient.

The implement 1 comprises a first unit composed of two extractingelements in the form of substantially kidney-shaped jaws 5 (one shown)each of which is provided with an arm 7. The arms 7 preferably exhibitor can exhibit a tendency to move the crown-engaging portions or pads 5aof the respective jaws 5 away from each other in order to provide roomfor positioning of the first unit of the implement 1 in a manner asshown in FIG. 1, i.e., so that the surfaces 19 of the pads 5a can engagetwo spaced apart portions of the external surface 3b of the crown 3 atlocations which are spaced apart from the edge 3a, i.e., the jaws 5 neednot come in contact with the gums.

Those ends of the arms 7 which are remote from the respective surfaces19 are connected to an annular member or eyelet 17 forming part of asecond unit of the implement 1. A sleeve 21 of the second unit surroundsthe arms 7 and is movable along the arms toward and away from theannular member 17 in order to permit the pads 5a of the jaws 5 to moveapart or to compel the pads 5a to move toward each other and to firmlyengage the adjacent portions of the external surface 3b of the crown 3.The sleeve 21 can carry one or more screws 21a or other suitablefastener or detent means to releasably hold the sleeve in a selectedposition, particularly in a position in which the surfaces 19 of thepads 5a of the jaws 5 are in pronounced frictional engagement with theadjacent portions of the external surface 3b of the crown 3. Thesurfaces 19 can be provided on elastic portions or inserts of the pads5a of the jaws 5, or such surfaces can be serrated and/or provided withembedded fragments of industrial diamonds or with embedded or adhesivelysecured fragments of other hard material which ensures the establishmentof a reliable frictional engagement with the crown 3 when the sleeve 21is caused to slide toward the crown between the two jaws 5.

The second unit of the implement 1 further comprises an elongatedrod-like handle or handgrip member 9 one end of which carries theannular member 17 and the other end of which has an externally threadedstub 11 receivable in a tapped bore of a force applying member 13indicated in FIG. 1 by a phantom line. FIG. 3 shows that the forceapplying member 13 is an elongated rod-shaped guide for a weight orhammer 15 which is reciprocable by hand in directions indicated by arrow15a in order to repeatedly strike an anvil 13a at that end of the member13 which is remote from the annular member 17. This results in repeatedapplication of a selected pulling force in the direction of arrow Xwhereby the crown 3 is loosened and is ultimately separated from therespective tooth portion.

The annular member or eyelet 17 acts not unlike a joint whichestablishes an articulate connection between the two units of theimplement 1 and enables the handle 9 of the second unit to change itsorientation for more convenient reciprocation of the hammer 15 towardand away from the anvil 13a. Since the pads 5a of the jaws 5 engage twospaced apart portions of the external surface 3b of the crown 3 atopposite sides of the crown, the improved implement 1 is much lesslikely to tilt the crown in the course of the extracting operation. Thisnot only reduces the likelihood of deformation of the crown 3 duringextraction but also reduces the likelihood of damage to the bondingmaterial which is used to secure the crown 3 to the portion of the toothnext to the tooth T of FIG. 1. Still further, the absence of undesirabletilting or other undesirable change of orientation of the crown 3 duringextraction ensures that the force which is to be applied in order toextract the crown need not be increased in the course of the actualextracting operation; this will be readily appreciated since the crown 3need not be tilted and/or otherwise misoriented while the hammer 15repeatedly strikes the anvil 13a of the force applying member 13. Inaddition, and since the jaws 5 do not and need not come in contact withthe edge 3a of the crown 3 and/or with the gums adjacent the edge 3a,the improved implement 1 is highly unlikely to cause discomfort to thepatient and/or infection or inflammation or bleeding or swelling of thegums as a result of extraction of the crown 3 from a wearer's mouth.

The annular member or eyelet 17 can be replaced with other suitablemeans for establishing an articulate connection between the handle 9 ofthe second unit and the arms 7 of the jaws 5. For example, the annularmember 17 can be replaced with a piece of flexible wire, with a piece ofcord or the like to thus establish a universal joint which enables thehandle 9 and the force applying member 13 to change their inclinationrelative to the arms 7 in any desired direction for more convenientmanipulation of the sleeve 21, fastener or fasteners 21a and hammer 15.

The surfaces 19 of the pads 5a of the jaws 5 can have a concave orslightly concave shape in order to more accurately conform to the shapesof adjacent portions of the external surface 3b of the crown 3. Thesurface 19 of one of the jaws 5 need not be an exact mirror image of theother surface 19; all that counts is to configurate and/or coat and/ordimension the surfaces 19 in such a way that they can reliably engageand grip the crown 3 in the course of the extracting operation. Theentire pads 5a of the jaws 5 can be made of a material which can bebrought into highly satisfactory frictional engagement with the externalsurface 3b of a crown. However, it is also possible to make the pads 5aof the jaws 5 from a material which can reliably engage the crown 3solely as a result of appropriate treatment (coating and/or rougheningand/or shaping) of the surfaces 19).

The fastener or fasteners 21a can be omitted if the internal surface ofthe sleeve 21 is coated with a friction generating material (e.g.,rubber) which ensures that the sleeve 21 will remain in a selectedposition, i.e., at a selected distance from the annular member 17.

The sleeve 21 can be replaced with an internally threaded nut which isto be rotated in order to move axially of the externally threaded arms 7to a selected position in which the pads 5a of the jaws 5 are maintainedin reliable frictional engagement with the adjacent portions of theexternal surface 3b of a crown 3.

The handle 9 of the second unit in the implement 1 of FIG. 2 carries anannular member or eyelet 17 for three discrete rings or eyelets 23. Eacheyelet 23 receives the inner end portions of the arms 7 of a discretepair of extracting elements or jaws 5. A sleeve 21 (only one shown) isprovided for each pair of arms 7 to move the pads 5a of the respectivejaws toward each other. The pads 5a of the median pair of jaws 5 whichare shown in FIG. 3 are in frictional engagement with the externalsurface 3b of a crown 3. The dimensions and/or shapes of the pads 5a ineach of the three pairs of jaws 5 are preferably different so that thedentist can select those pads which are best suited for satisfactoryfrictional engagement with the external surface 3b of a particular crown3. A second pair of jaws 5 in the implement 1 of FIG. 2 can be used toengage the external surface 3b' of the crown 3' which is adjacent thecrown 3, for example, when the crowns 3 and 3' are soldered or otherwiserigidly connected to each other to jointly form a bridge. The finish ofthe surfaces 19 on the pads 5a of one pair of jaws 5 of the three pairswhich are shown in FIG. 2 can be different from pair to pair. This, too,contributes to versatility of the implement 1 which is shown in FIG. 2.

The annular member 17 and the three eyelets 23 together form what can betermed a universal joint which enables the handle 9 of the second unitof the implement 1 of FIG. 2 to change its orientation relative to oneor more pairs of jaws 5 in engagement with one or more crowns in anydesired direction. The construction of the force applying member 13 (notshown in FIG. 2) and of its anvil 13a and hammer 15 can be the same asshown in FIG. 3.

The implement of FIG. 3 differs from the implement 1 of FIG. 2 in thatthe second unit comprises a two-armed lever 27 which constitutes aweighbeam and is provided with rings or eyelets 23 for the arms 7 of thethree pairs of jaws 5. In addition, the weighbeam 27 carries twohook-shaped extracting elements 30 (hereinafter called hooks) whichalternate with the pairs of jaws 5 and can be used to engage theconnectors 33 between pairs of neighboring crowns forming part of abridge. The hooks 30 must be slipped under the connectors 33 and arethereupon pulled in a direction away from the gums G in order to detachthe bridge from the corresponding teeth or portions of teeth in apatient's mouth.

A piece of flexible wire 25, an elastic band or a piece of cord isprovided to connect the median portion of the weighbeam 27 to the handle9.

FIG. 3 shows a bridge having three crowns 3, 3', 3" and two connectors33 between such crowns. All of the extracting elements which are shownin FIG. 3 can be put to use simultaneously, i.e., each pair of jaws 5can engage one of the three crowns and each of the two hooks 30 canengage one of the connectors 33. This ensures a highly satisfactorydistribution of pulling forces and reduces the likelihood ofmisorientation of the bridge during extraction from a patient's mouth.Uniform distribution of pulling forces is also ensured by the rings oreyelets 23, weighbeam 27 and wire 25.

Each pair of jaws 5 and each of the two hooks 30 can be readily detachedfrom the respective ring 23, i.e., the number of extracting elements ofthe first unit in the implement of FIG. 3 can be altered at will. Ifonly the median pair of jaws 5 is retained, the implement 1 of FIG. 1can be said to constitute a functional equivalent of the implement 1which is shown in FIG. 1. The sleeves 21 were omitted in FIG. 3 for thesake of clarity.

FIG. 4 shows an extracting implement 29 in the form of scissors 29. Thetwo elongated halves 29A, 29B of the scissors 29 are pivotally connectedto each other by a pin 29D, one end of each half carries a handle orhandgrip portion 31, and the other end of each half carries a jaw 5,e.g., a jaw having a substantially kidney-shaped pad 5a. The user of thescissors 29 moves the pads 5a apart prior to engaging the surfaces 19with adjacent portions of the external surface of a crown, and thehandles 31 act not unlike the pulling force applying means 13 to extracta properly engaged crown from the mouth of a patient.

The lower portions of the halves 29A, 29B of the scissors 29 (as seen inFIG. 4) can be surrounded by a sleeve 21 or the like (not shown) inorder to prevent any movement of the pads 5a away from each other in thecourse of the actual extracting operation, namely when the handles 31are used to exert a pulling force in the direction of arrow X.

The sleeve 21 or sleeves 21 can be omitted, especially in an implementwhich employs a single pair of jaws 5, because the dentist can use twofingers of one hand to press the pads 5a against the external surface 3bof a crown 3 while the other hand operates the hammer 15 or exerts apull upon the handles 31 in order to extract the crown.

The implement 29 of FIG. 4 can be used with particular advantage when acrown 3 is already loose, i.e., when it is not necessary to apply apulsating force because the crown can be extracted by the simpleexpedient of exerting a single pull in the direction of arrow X. Theimplement of FIGS. 1, 2 or 3 can be used in the same way, i.e., it isnot necessary to cause the hammer 15 to repeatedly strike the anvil 13aif the crown or bridge is loose so that it can be extracted with theexertion of a relatively small force.

FIG. 5 shows as portion of a simple implement which can be used toloosen and extract a bridge composed of two crowns 103, 103' and aconnection or connector 133 between the crowns. The first unit of thisimplement comprises a single hook 130 of the type known as shepherd'scrook which can be readily placed around the connector 133 without eventouching the gums G and without coming close to the edges 103a, 103a' ofthe crowns, and the handle 109 of the second unit is thereupon caused toexert a pull (e.g., by being connected to the force applying member 13of FIG. 3) so that the bridge becomes separated from the correspondingteeth or fragments of teeth, and more particularly from the preparationwhich is used to bond the internal surfaces of the crowns 103, 103' tothe respective teeth.

The tip of the hook 130 is preferably rounded to further reduce thelikelihood of injury to the gums G when the hook is caused to engage theconnector 133. As a rule, the connector 130 is spaced apart from theedges 103, 103' and from the gums G.

FIG. 6 shows a modified implement for removal of larger bridges, e.g.,of a bridge 35 of the type shown in FIG. 7.

The first unit of the implement of FIG. 6 has three discrete extractingelements in the form of hooks 130 which are preferably articulatelyconnected to the handle 109 of the second unit. For example, theconnection between a holder 130A for the hooks 130 and the handle 109can comprise a universal joint or any other suitable joint 37 (e.g., apiece of wire or cord or elastic band), and each hook 130 can bearticulately connected to the holder 130A, e.g., by a ring or eyelet123. This renders it possible to select the angular positions of theshanks of the hooks 130 practically at will and to thus ensure properengagement between such hooks on the one hand and selected connectors 33of the bridge 35 on the other hand.

The positions of the hooks 130 of FIG. 6 during engagement with threeconnectors 33 of the bridge 35 of FIG. 7 are indicated by broken lines.The crowns of the bridge 35 are numbered 11 to 16 and 21 to 26; theleft-hand hook 130 engages a connector 33 between the teeth 14 and 15;the median hook 130 engages a connector 33 between crowns 11 and 21; andthe right-hand hook 130 engages a connector 33 between the crowns 23 and24. The number of hooks 130 can be reduced to two or one or increased tofour or more, depending on the nature of the bridge which is to beextracted.

As already described with reference to FIG. 3, the first unit of theimproved implement can include one or more hooks and one or more pairsof jaws; such implement can be used in lieu of the implement of FIG. 6to even more reliably engage the bridge 35 at as many as eight differentspace-apart locations and to even further reduce the likelihood oftilting of the crowns 11 to 16 and 21 to 26 during extraction of thebridge 35.

A hook 30 or 130 can be replaced with an elongated flexible extractingelement 215 of the type shown in FIGS. 8 to 10. This extracting elementis a piece of wire 214 (preferably consisting of numerous metallicfilaments, particularly steel filaments) with two ends which areprovided with enlarged heads 217. The second unit of the implement ofFIGS. 8 to 10 comprises a substantially flat rectangular or squarehousing or casing 209 having two lateral sockets each of which includesan elongated hole or bore 211, an elongated open slot 213 which extendsfrom the respective hole 211 to the external surface of the housing 209,and an enlarged portion 219 for a head 217 of the flexible extractingelement 215. The holes 211 are preferably parallel or nearly parallel toeach other, and their diameters D are slightly larger than the diameterd of the wire 214 of the flexible element 215 but at least slightlysmaller than the diameters of the enlarged portions 219.

The enlarged portions or heads 217 can be obtained by soldering,welding, press fitting or otherwise securing suitable sleeves or caps tothe ends of the flexible element 215. The diameters of the heads 217 areselected in such a way that they fit snugly into the respective enlargedportions 219 while the adjacent portions or extremities 218 of theflexible element 215 are received in the holes 211 of the respectivesockets. The width of the narrowest portions of the slots 213 (at therespective holes 211) can at least match the diameter d of the wire 214of the flexible element 215 so that the extremities 218 of this elementcan be readily inserted into and withdrawn from the sockets indirections from the left and from the right, as seen in FIG. 8.

One of the heads 217 can be more or less permanently anchored in thehousing 209. This can be seen in the right-hand portion of FIG. 8 wherethe enlarged portion 219 is tapped, as at 221, to accept the shank of athreaded fastener 223 serving to preferably releasably capture orconfine the right-hand head 217 in the enlarged portion 219 of therespective socket. In addition to or in lieu of the fastener 223, themeans for confining one of the heads 217 or both heads 217 in theenlarged portions 219 of the respective sockets can comprise a cover,closure or lid 224 (indicated in FIG. 8 by broken lines) pivotable toand from an operative position in which it overlies the adjacent ends ofthe sockets. It is also possible to employ a cover 224 having two armsone of which can be pivoted to and from a position of overlap with theright-hand head 217 and the other of which can be pivoted to and from aposition of overlap with the left-hand head 217. The cover 224 can beprovided with an opening or with two openings, each in register with oneof the holes 211.

The housing 209 is provided with a recess 225 which is located betweenthe sockets (and more specifically between the holes 211 in thehousing), with a through hole or opening 229 adjacent the enlargedportions 219 of the sockets, and/or with yoke 233. The purpose of therecess 225 and/or hole 229 and/or yoke 233 is to permit engagement witha customary dentist's tool 235 (e.g., a hook at one end of a handle) oranother dentist's tool 237, namely a stepped tool with a pallet at oneend. Such tool or tools are used to exert upon the housing 209 a pull ina downward direction, as viewed in FIGS. 8 to 10. The recess 225 ispreferably bounded in part by an inclined bottom surface 227, and theopening 229 can be bounded in part by an inclined bottom surface 231.

The operation of the implement of FIGS. 8 to 10 is as follows:

The fastener 223 is applied to secure the right-hand head 217 of FIG. 8in the enlarged portion 219 of the respective socket. The left-hand head217 is not confined in the housing 209 and can be caused to pass betweenthe gums G and the connector 133 of the bridge including the crowns 103,103' of FIG. 5 (or between the gums and any of the connectors 33 in thebridge 35 of FIG. 7). The flexible element 215 is then looped, and itsexposed extremity 218 is introduced into the still unoccupied hole 211so that the head 217 enters the enlarged portion 219 of the left-handsocket in the housing 209 of FIG. 8.

The surface bounding the recess 225, the surface bounding the opening229 and/or the yoke 233 is then engaged by a tool 235 and/or 237 toexert a pull in the direction of arrow X and to thus exert a pull uponthe connector 33 which is engaged by the bight of the looped flexibleelement 215 while the two heads 217 of the element 215 are securelyanchored in the enlarged portions 219 of the respective sockets. If thedentist realizes that the engagement of the housing 209 by a tool 235 or237 at the recess 225 is not very convenient or not the mostsatisfactory way of exerting a pull upon the looped flexible element215, the dentist causes the tool to engage the surface bounding theopening 229 or to engage the yoke 233. Thus, the dentist has the optionof selecting the application of a pulling force in a manner which ismost convenient to the dentist and which ensures most convenient andpainless extraction of a bridge.

The extremities 218 of the flexible element 215 can be dimensioned insuch a way that they must be forced from the respective slots 213 intothe adjacent holes 211. This greatly reduces the likelihood ofaccidental removal of such extremities from the respective sockets priorto tightening of the flexible element 215, i.e., prior to start of theactual extracting operation.

Two or more implements of the type shown in FIGS. 8 to 10 can be usedsimultaneously, e.g., in lieu of the hooks 130 which are shown in FIG.6, to reduce the likelihood of tilting of crowns during extraction of abridge having two or more connectors 33. If two or more implements ofthe type shown in FIGS. 8 to 10 are used, the dentist will preferablyrepeatedly switch from pulling with one of the looped flexible elements215 to pulling with another flexible element 215 and so forth in orderto reduce the likelihood of a change of orientation of the bridge in thecourse of an extracting operation.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic and specific aspects of my contributionto the art and, therefore, such adaptations should and are intended tobe comprehended within the meaning and range of equivalence of theappended claims.

I claim:
 1. An implement for extracting dental prostheses of the typeaffixed to at least one tooth and having at least one portion spacedapart from the gums of the wearer, comprising a first unit including twoextracting elements engageable with the at least one portion of theprosthesis to be extracted, each of said extracting elements including ajaw and each of said jaws having an elongated arm; and a second unitincluding means for applying to said extracting elements a force in adirection away from the gums of the wearer to thereby separate theprosthesis from the at least one tooth, said force applying meansincluding means for moving said jaws between first positions in whichsaid jaws provide room for the at least one portion of a prosthesistherebetween and second positions in which the jaws clamp the at leastone portion of the prosthesis between them, said moving means comprisinga sleeve which surrounds and is slidable along said arms.
 2. Theimplement of claim 1, wherein said jaws include elasticprosthesis-engaging portions.
 3. The implement of claim 1, wherein saidjaws have roughened prosthesis-engaging surfaces.
 4. The implement ofclaim 3, wherein said surfaces are connected with fragments of diamonds.5. An implement for extracting dental prostheses of the type affixed toat least one tooth and having at least one portion spaced apart from thegums of the wearer, comprising a first unit including at least oneextracting element engageable with the at least one portion of theprosthesis to be extracted, said at least one extracting elementincluding an elongated flexible element having a first end and a secondend; and a second unit including means for applying to said at least oneextracting element a force in a direction away from the gums of thewearer to thereby separate the prosthesis from the at least one tooth,said force applying means comprising a housing having means foranchoring said ends therein subsequent to looping of said flexibleelement around the at least one portion of the prosthesis to beextracted.
 6. The implement of claim 5, wherein said ends include headsand said anchoring means includes two spaced apart sockets provided insaid housing, one for each of said ends and each having an enlargedportion for the respective head.
 7. The implement of claim 6, whereinsaid anchoring means further comprises means for releasably confining atleast one of said heads in the enlarged portion of the respectivesocket.
 8. The implement of claim 7, wherein said confining meanscomprises a threaded member mating with said housing.
 9. The implementof claim 7, wherein said confining means comprises a closure whichoverlies the enlarged portion of at least one of said sockets.
 10. Theimplement of claim 6, wherein said flexible element has a first diameterand each of said sockets includes a hole having a second diameterslightly greater than said first diameter.
 11. The implement of claim10, wherein at least one of said heads has a diameter greater than saidsecond diameter.
 12. The implement of claim 5, wherein said second unitfurther comprises means for pulling said housing and said housingincludes at least one portion which is engageable by said pulling means.13. The implement of claim 12, wherein said at least one portion of saidhousing includes a recess.
 14. The implement of claim 12, wherein saidat least one portion of said housing includes a hole.
 15. The implementof claim 12, wherein said at least one portion of said housing includesa yoke.
 16. An implement for extracting dental prostheses of the typeaffixed to at least one tooth and having at least one portion spacedapart from the gums of the wearer, comprising a first unit including twoextracting elements engageable with the at least one portion of theprosthesis to be extracted, each of said extracting elements including ajaw and each of said jaws having an elongated arm; and a second unitincluding means for applying to said extracting elements a force in adirection away from the gums of the wearer to thereby separate theprosthesis from the at least one tooth, said force applying meansincluding means for moving said jaws between first positions in whichsaid jaws provide room for the at least one portion of a prosthesistherebetween and second positions in which the jaws clamp the at leastone portion of the prosthesis between them, said moving means includingan internally threaded nut surrounding said arms.
 17. An implement forextracting dental prostheses of the type affixed to at least one toothand having at least one portion spaced apart from the gums of thewearer, comprising a first unit including a plurality of extractingelements engageable with the at least one portion of the prosthesis tobe extracted; and a second unit including means for applying to saidextracting elements a force in a direction away from the gums of thewearer to thereby separate the prosthesis from the at least one tooth,said force applying means comprising means for movably coupling saidextracting elements to each other and said coupling means comprising atleast one annular member.
 18. The implement of claim 17, wherein saidsecond unit includes shears having two elongated halves each having ahandle at one end and carrying one of said jaws at the other end, andmeans for pivotally connecting said halves to each other intermediatesaid ends thereof.
 19. An implement for extracting dental prostheses ofthe type affixed to at least one tooth and having at least one portionspaced apart from the gums of the wearer, comprising a first unitincluding a plurality of extracting elements engageable with the atleast one portion of the prosthesis to be extracted; and a second unitincluding means for applying to said extracting elements a force in adirection away from the gums of the wearer to thereby separate theprosthesis from the at least one tooth, said force applying meanscomprising means for movably coupling said extracting elements to eachother and said coupling means comprising at least one weighbeam.